This invention relates to drive mechanisms and, in particular, to magnetic drives.
Mechanical gears for transferring rotary power about one axial direction to about another axial direction are well known in the gearing art. For example, a bevel gear, which typically has gear teeth projecting from the side of one axial element and gear teeth projecting along another axial element, is typically used to transfer rotary power at right angles.
Unfortunately, mechanical gears have several disadvantages. One disadvantage is mechanical wear due to the interaction of the gear teeth on one element with the gear teeth on the other element. Another disadvantage is the inability to readily vary the amount of power transferred from one element to the other element. A further disadvantage occurs if the gears are to be disengaged and engaged, because some type of clutch, mechanical or fluid, must also be added, increasing the cost and complexity. Still another disadvantage is the complexity encountered when two motors are driving the same element simultaneously.
The present invention substantially reduces or eliminates at least some of the problems and disadvantages associated with conventional mechanical gears for transferring rotary power about one axial direction to about another axial direction. To achieve this, the present invention, in particular embodiments, provides a variable ratio angled magnetic drive.
In certain embodiments, the present invention provides an angled magnetic drive. The magnetic drive includes a motor that is operable to generate rotary motion about a first axis. The magnetic drive also includes a driving member that is coupled to the motor and rotated by it. The driving member includes a plurality of magnets coupled to one of its faces. The magnetic drive additionally includes a driven member mounted to rotate about a second axis oriented at an angle to the first axis. At least part of a first face of the driven member is located in proximity to the face of the driving member, such that the driven member is magnetically coupled to the driving member when the motor rotates the driving member, the rotation of the driving member producing rotation of the driven member.
In other embodiments, the present invention provides a second angled magnetic drive. This magnetic drive includes a first motor that is operable to generate rotary motion at a motor shaft about a first axis, and a first driving member that is coupled to the motor shaft to rotate about the first axis. The first driving member includes a plurality of magnets coupled to one of its faces. The magnetic drive also includes a second motor that is operable to generate rotary motion at a motor shaft about a second axis, and a second driving member that is coupled to the motor shaft of the second motor to rotate about the second axis. The second driving member includes a plurality of magnets coupled to one of its faces. The magnetic drive additionally includes a driven member mounted to rotate about a third axis oriented at an angle to the first axis and the second axis. At least part of a first face of the driven member is located in proximity to the face of the first driving member, and at least part of a second face of the driven member is located in proximity to the face of the second driving member. The driven member is magnetically coupled to the first driving member when the first motor rotates the first driving member and to the second driving member when the second motor rotates the second driving member, such that the rotation of one or both of the first driving member and the second driving member produces rotation of the driven member.
The present invention provides several technical advantages. For example, because a drive constructed in accordance with the present invention does not use mechanical gears to transfer rotary power between a driving member and a driven member, the drive is not susceptible to mechanical wear due to the interaction of gear teeth between elements. Another advantage is the ability, at least in certain embodiments, to readily vary the ratio between a driving element and a driven member. This allows the power being transferred to the driven member to be readily and/or smoothly varied. An additional advantage is the ability to readily engage and disengage a driving member and a driven member. A further advantage of the present invention is the ability to drive one driven member by two different driving members, thereby providing redundancy in case one of the motors fails.
Other technical advantages will be readily apparent to one skilled in the art from the following figures, description, and claims.